In the medical field, it is a general practice to preserve and distribute multiple drug ingredients in the state of being separately contained in packages and to mix the drug ingredients immediately before dosing. For example, as an infusion preparation for IVH, one that contains carbohydrates and amino acids as nutrition sources together with an electrolyte is used, and, in this case, since the liquid containing glucose sugar and the amino acids is liable to be denatured through the Maylard reaction, there is generally adopted a method in which the glucose sugar and the amino acids are contained in separate packages until they are mixed with each other immediately before dosing.
There have been applied a large number of packages with multiple chambers the inside of which is partitioned into multiple regions and which enables the above-mentioned mixing to be carried out in a sealed package (see, for example, Patent document 1: Japanese Patent No. 2675075; Patent document 2: Japanese Patent No. 2675049; Patent document 3: Japanese Utility Model Laid-open No. Hei 5-5138; and Patent document 4: Japanese Patent No. 3016348). Each of these relates to a package with multiple chambers in which the inside of the package is partitioned into multiple chambers by a weak seal part(s) provided at a part thereof, and, at the time of use, the weak seal part(s) is broken (broken through) by hands or with tools, whereby multiple contents therein can be mixed with each other under a hermetically sealed condition. Polyethylene and polypropylene are primarily used as a material of the seal layer, and provision of the weak seal part(s) at a part of a package by use of such a material can be carried out comparatively easily.
Here, in the case of preserving specified liquid contents, the use of a package with the seal layer formed of polyethylene or polypropylene may leads to a change in the composition of the liquid contents. To be more specific, in the case where a drug for dosing which contains a medicine such as infusion, medical liquid, radiographic agent, hormone agent, radioactive medicine, circulatory organ drug, digestive system preparation, protein amino preparation, circulatory system preparation, enzyme preparation, metaboric medicine, antibiotic, anti-inflammatory agent, tumor medicine, biological preparation, etc., or a vitamin agent or the like as an effective ingredient is the content liquid, a trace of an element (for example, manganese) or a vitamin or the like contained in the medicine or drug for dosing may be adsorbed on the package inside wall or may interact with the seal layer (olefin resin such as polyethylene and polypropylene), or, conversely, low molecular weight components such as additives or monomers eluted from the seal layer and other low molecular weight components of the printing inks or the adhesive may interact with the contents, with the result that perfect dosing of the effective ingredient cannot be achieved at the time of use.
As a package capable of preventing such an interaction between the effective ingredient of the contents and the package inner wall, there have been proposed packages using a cyclic polyolefin for the package inner wall (see, for example, Patent document 5: Japanese Patent Laid-open No. 2003-24415; Patent document 6: Japanese Patent Laid-open No. Hei 11-158061; and Patent document 7: Japanese Patent Laid-open 2002-193816). However, these packages are not ones designed on the assumption that the inside of the package is partitioned into multiple chambers. The cyclic polyolefin is a material very poor in seal property, and it is very difficult to partition the inside of these packages directly into multiple chambers (to provide the packages with a weak seal part(s) controlled in seal strength).
As a method for imparting a seal property to a cyclic polyolefin, a technology of contriving an enhanced heat seal property by mixing the cyclic polyolefin with a linear polyolefin is proposed in Patent document 8: Japanese Patent Laid-open No. 2000-70331.
However, when the linear polyolefin is mixed, adsorption of the effective ingredient onto the linear polyolefin is inevitable. Moreover, when the cyclic polyolefin is mixed with a linear polyolefin, transparency may be lowered, or the low molecular weight components such as additives and monomers contained in the linear polyolefin might be eluted into the contents, therefore, the packages thus obtained by the mixing still have room for improvement, particularly where the packages are for medical use.
Thus, there has been a request for a technology by which a suitable seal property necessary for forming the inner surfaces of the walls of a package with multiple chambers can be imparted to a cyclic polyolefin, without spoiling the characteristic features of the cyclic polyolefin, i.e., those features of the cyclic polyolefin by which the adsorption of the effective ingredient of the contents onto the cyclic polyolefin can be obviated, and by which it is ensured that even where olefin resin, printing ink, adhesive or the like is used in or on other layers than the heat seal layer forming the package inner surfaces of the walls, the elution of low molecular weight components of the olefin resin or the like from the other layers into the contents can be prevented from occurring.
The present invention has been made in consideration of the above-mentioned circumstances. Accordingly, it is an purpose of the present invention to provide a package with multiple chambers in which the package inner wall would not adsorb or hold an effective ingredient of the contents, by which it is ensured that, even where olefin resin, printing ink, adhesive or the like is used in or on other layers than the heat seal layer forming the package inner surfaces of the walls, the elution of low molecular weight components of the olefin resin or the like from the other layers into the contents can be prevented from occurring, and which, with the appropriate heat seal property and thermal resistance thereof, is preferable particularly for medical use.